1. Field of the Invention
The present invention relates to a device for processing a plate-shaped workpiece, and in particular to a plate processing device provided with a vertically acting ram, such as, for example, a shearing machine, press brake, or press machine.
2. Description of Prior Art
A ram with free vertical movement installed on a commonly known plate processing device such as a shearing machine or a press machine is usually guided in freely reciprocal movement by means of a ram guide mechanism mounted on a frame.
This ram guide mechanism generally operates through a gib between a guide member mounted vertically on a frame and the ram. Conventionally, therefore, in order to provide reliable surface contact for the gib and the guide member with the ram, high precision processing is necessary, and adjustment at the time the unit is assembled is very troublesome, causing problems in the assembly operation problem.
In addition, in the case where a conventional ram guide mechanism is adopted on a shearing machine, when adjusting the space between the upper and lower blades to conform to the plate thickness of a plate-shaped workpiece which is to be sheared, time is required to make the adjustment so that improvement of the operating efficiency is a problem.
Also, in a plate processing device such as a shearing machine or a press brake it is usual to provide a back gauge device in order to position the workpiece once the trailing edge is reached. When bending and shearing the workpiece, after the end is reached and the workpiece is positioned, this back gauge device is moved away from the workpiece a suitable distance. Accordingly, in a conventional back gauge device, when the end of the workpiece is reached there is no way to buffer the shock, and after the back gauge device is moved away from the work piece, it is not easy to quickly repeat the operation.
In addition, in a plate processing device such as a shearing machine, it is necessary to firmly secure the workpiece to the work table when the shearing process is being performed. Conventionally, a large volume of high pressure operating oil is supplied to the shearing means in the plate pressing device, rapidly activating the plate pressing device with a large force. Therefore, when the workpiece is secured by a pressure pad on the device, the pressure pad impacts the workpiece and a large impact noise is created, which is a problem.